/**
 * @internal
 * The structure of a registered interceptor.
 */
export interface Interceptor<V> {
    onFulfilled: (value: V) => V | Promise<V>;
    onRejected?: (error: unknown) => unknown;
}
/**
 * @internal
 * Manages a collection of interceptors.
 */
export declare class InterceptorManager<V> {
    private handlers;
    /**
     * Adds a new interceptor to the manager.
     *
     * @param onFulfilled - The function to run when the promise is fulfilled.
     * @param onRejected - The function to run when the promise is rejected.
     * @returns An ID that can be used to remove the interceptor later.
     */
    use(onFulfilled: (value: V) => V | Promise<V>, onRejected?: (error: unknown) => unknown): number;
    /**
     * Removes an interceptor from the manager by its ID.
     *
     * @param id - The ID of the interceptor to remove.
     */
    eject(id: number): void;
    /**
     * Iterates over all registered interceptors.
     *
     * @param fn - The function to execute for each interceptor.
     * @internal
     */
    forEach(fn: (interceptor: Interceptor<V>) => void): void;
}